I have been culturing Harpacticoids copepods (Tigriopus Californicus) for nearly three years now, primarily for the three dragonets which reside in our reef tank. A male & female Mandarin Dragonets (Synchiropus Splendidus) and a female Ocelatted Dragonet (Synchiropus Ocellatus).
I chose to culture Harpacticoids copepods as they are “benthic” or substrate-dwelling copepods, feeding on micro-algae (or the bacteria that grow on it) and detritus. The copepods are harvested once a week when I also complete a 10% water change. The harvested copepods are rinsed with fresh sea water and added to the tank at night when the lights are low and the protein skimmer is off. I also turn off the circulators to give them a chance to sink to the substrate.
To culture your own copepods you will need …
- live copepods
- a culture vessel
- air pump
- rigid & flexible air line + flow valve
- two cable glands (M20 x 1.5cm
- an airlock
- copepod feed
- sea water (RO water + sea salt)
Culture vessel. My culture vessel is a lidded 11 litre (H:190mm, W:260mm & D: 365mm) white plastic box which has been adapted with a small hole drilled in the side to fit air line and a small hole in the lid to fit a airlock. I have marked the outside of the culture vessel with a line which enables weekly water changes and ensures I can see any evaporation and top up with RO water. Your culture vessel can be anything from a small aquarium to a plastic or Tupperware container that holds enough water. Deep containers are not meant to work, but I’ve never tried.
Air pump & flexible hose. The flexible air hose is attached to the air pump. (My air pump has two individually adjustable air outlets, as I also culture phytoplankton using one air pump). Cut to length the tubing is attached to the outside of the culture box using one of the connectors. Attach the rigid length of tube inside the culture box to the same connector.
Airlock. The airlock (purchased from a local brew shop) is attached to the lid using the second connector.
Culture water. Fresh seawater (RO water & sea salt) to fill your culture vessel. The suggested specific gravity is usually around 1.020 SG. The salinity of my copepod culture water matches my reef tank (1.025 SG, 35 PPT). My theory – this reduces shock and increasing survival rates when added to the tank. I make up a batch of 2o litres of sea water at a time for 10% weekly water change and rinsing the harvested copepods.
Fill your container with the seawater, no more than about two-thirds full. On the outside of the culture vessel mark the top of the water line (*see below). Turn on air pump and adjust flow until you only have a slow bubble rate, roughly one bubble per 1-2 seconds.
Add Copepod feed. To begin with add a very small amount of copepod feed to lightly colour the culture water until you copepods multiply. Do not add too much, or the water will foul and culture will probably crash.
Add your live copepods. Your set up is now good to go, so add your copepods and place the lid on. The lid helps reduce evaporation. Any evaporation of water ( water will be below your water level mark) should be replaced with RO not sea water – as this will effect the salinity of your copepod culture and may cause it to crash. Top up with RO to until your culture water returns to your water level mark
Over the next few weeks, your copepods will reproduce and once they get to a certain population level you will see an “explosion” of copepods in your culture vessel. Feed as necessary to keep the water lightly tinted. As I mentioned earlier, my copepod culture has been going a few years now and I feed the copepods once a week with phytoplankton (Nannochloropsis Oculata) and 2 to 3 times a week with a sprinkle of Spirulina Powder.
Harvesting copepods. I harvest my copepods weekly. I use a turkey baster to siphon off the copepods into a small jug, the process allows me to also complete a concurrent 10% water change .
Before I’ve finished with the copepod culture I replace the siphoned off culture water with clean sea water to the water level mark on outside of the culture vessel and add the phytoplankton. If you want to know how to culture your own phytoplankton here’s my post …. just for you culturing phytoplankton
The collected copepods are poured into a 200 micron sieve to drain off the culture water and rinsed with a little fresh salt water in the sieve.
Turning the sieve over a clean glass jug I rinse out the copepods with small amount of clean salt water and add a little phytoplankton to the jug.
The copepods are now ready to add to the tank, which I do in the evening when tank lights are dimming; the protein skimmer and circulators are off.
2017 additional note: I have built a second copepod culture vessel, here is link to the blog post post giving step by step instructions on how to DIY a culture vessel.
A note on dragonets: Please, please, please if you want to keep dragonets do your homework before you buy, there are some great articles available online. Dragonets have special dietary needs and without their proper food they end up starving to death. As a bare minimum you need a 75-gallon+ well-established tank with a lot of live rock and a substantial copepod population as getting a dragonet especially a mandarin to take prepared foods is one of the most challenging tasks for a hobbyist. We are very lucky as all three dragonets have taken to eating reef paste as a supplement to the copepods which they constantly scan for and pick off the live rock.